Auckland Air Emissions Inventory: 2004 - February 2006 Technical Publication 292 - Auckland Council
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Auckland Air Emissions Inventory: 2004 February 2006 Technical Publication 292 Auckland Regional Council Technical Publication No. 292, February 2006 ISSN 1175-205X ISBN 1877416 223 www.arc.govt.nz
TP292 Auckland Air Emissions Inventory 2004
Auckland Air Emissions Inventory:
2004
Authors
J. L. Metcalfe
G. W. Fisher
M. W. Sherman
and
G. I. Kuschel (Auckland Regional Council)
Prepared for Auckland Regional Council
ENDPOINT Client Report 200502
February 2006
Endpoint Ltd
PO Box 37 656, Parnell, Auckland
Phone +64-9-368 5971, Fax+64-9-368 5972
© All rights reserved. This publication may not be reproduced or copied in any form without the permission of the client. Such
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TP292 Auckland Air Emissions Inventory 2004TP292 Auckland Air Emissions Inventory 2004
Contents
Executive Summary i
1 Introduction 1
1.1 Background 2
1.2 Pollutants 3
1.3 Sources of Emissions 6
1.4 Results for Ambient Air Pollutants 6
1.5 Results for CO2 8
1.6 Results for PM10 in the Urban Area 9
1.7 Results by Season 9
2 Domestic Emissions 10
2.1 Domestic Sources 10
2.2 Domestic Heating Emissions Estimation 12
2.3 Emissions Estimation for Other Domestic Sources 14
3 Transport Emissions 16
3.1 Transport Sources 16
3.2 Motor Vehicle Emissions Estimation 17
3.3 Emissions Estimation for Other Transport Sources 23
4 Industrial Emissions 25
4.1 Industrial Sources 25
4.2 Industrial Emissions Estimation 26
5 Trends 27
5.1 Overall Trends 28
5.2 Trends in Domestic Heating Emissions 29
5.3 Trends in Motor Vehicle Emissions 31
6 Unaccounted Emissions 33
6.1 Secondary Particulate 33
6.2 Sea Salt and Wind Blown Dust 33
6.3 Unaccounted Transport Sources 34
6.4 Likely Contribution of Unaccounted Emissions to Ambient PM10 35
TP292 Auckland Air Emissions Inventory 20047 Conclusions and Recommendations 37
7.1 Conclusions 37
7.2 Recommendations for future work 39
8 References 41
Appendix 1: Summary Tables 43
Appendix 2: Industrial Sources 48
Appendix 3: Sensitivity Analysis 50
Sensitivity Analysis for Domestic Heating Emissions 50
Sensitivity Analysis for Motor Vehicle Emissions 51
Appendix 4: Comparison of BEPM with NZTER 53
Appendix 5: Comparison with Previous Inventories 55
Acknowledgements
This report has been prepared by Jayne Metcalfe, Gavin Fisher and Micah Sherman of
Endpoint Ltd, with assistance from Gerda Kuschel of Auckland Regional Council.
Technical assistance is acknowledged from Emily Wilton (Environet) and from Bob Joynt
and Len Ng (Environment Protection Authority of Victoria, EPAV).
Valuable review comments have been received from Kevin Mahon and Janet Petersen
(Auckland Regional Council, ARC), and assistance from Surekha Sridhar (Auckland
Regional Council, ARC) with formatting and editing.
TP292 Auckland Air Emissions Inventory 2004Page i
Executive Summary
This inventory estimates the emissions to air in the Auckland region from four major
sectors (transport, domestic, industry and biogenic) with emphasis on emissions of four
key ambient air pollutants (PM10, NOx, CO, VOCs), assuming a base year of 2004.
Emissions are broken down:
sectorally (for the four major categories)
spatially (for the entire region versus the urban area only), and
seasonally (for a typical winter’s day versus a typical summer’s day).
An Auckland Air Emissions Inventory was first prepared in 1993. An upgrade of the
emissions inventory commenced in 1998 undertaken by the Environment Protection
Authority of Victoria. This report updates the 1998 inventory to produce air emissions
estimates for 1993, 2004, 2011 and 2021.
Emissions are estimated for fine particles (PM10), oxides of nitrogen (NOx), carbon
monoxide (CO), volatile organic compounds (VOCs), sulphur dioxide (SO2) and carbon
dioxide (CO2). This report focuses primarily on PM10 because ambient concentrations
measured in Auckland have exceeded the National Environmental Standard (NES) of
50μg m-3 at both peak traffic and urban monitoring sites. PM10 is considered a surrogate
for health impacts from all air pollutants.
Breakdown of Emissions by Sector
The annual estimates of the total emissions across the entire Auckland region in 2004 of
the six contaminants are approximately:
5,900 t/yr PM10 (47% transport, 39% domestic, 14% industry)
35,000 t/yr NOx (83% transport, 13% industry, 3% biogenic)
171,200 t/yr CO (85% transport, 13% domestic, 2% industry)
64,200 t/yr VOC (52% transport, 26% industry, 13% biogenic, 9% domestic)
4,200 t/yr SO2 (65% transport, 32% industry, 3% domestic)
8,930,000 t/yr CO2 (48% transport, 46% industry, 6% domestic)
Looking at the total annual emissions of all ambient air pollutants (excluding CO2), the
single largest individual sources in the sectors are:
motor vehicles* at 70% and domestic heating+ at 10%
* motor vehicles are responsible for approximately 91% of the total transport sector emissions
+
domestic heating is responsible for approximately 85% of the total domestic sector emissions
TP292 Auckland Air Emissions Inventory 2004Page ii
Breakdown of Emissions by Location
The density of emissions varies across the region with the urban area, which represents
less than 25% of the total regional landmass, contributing the majority of the total
regional emissions for each pollutant as follows:
83% regional PM10 (4,900 t/yr)
82% regional NOx (28,600 t/yr)
91% regional CO (155,600 t/yr)
82% regional VOC (52,600 t/yr)
50% regional SO2 (2,100 t/yr)
78% regional CO2 (6,920,000 t/yr)
Breakdown of Emissions by Season
Seasonal variations in emissions are significant, both in terms of the amount as well as
the relative contributions of sources, particularly for PM10 as follows:
PM10 emissions on a typical winter weekday (29t/day) are nearly three times those
of a typical summer weekday (10t/day).
Domestic sources (principally domestic heating) account for 64% of PM10 on a
typical winter weekday (June-August) but fall to 2% of PM10 on a summer
weekday (December-February).
Transport sources (principally motor vehicles) account for 27% of PM10 on a
typical winter weekday (June-August) but rise to 74% of PM10 on a summer
weekday (December-February).
Trends
Emissions have been estimated from 1993 out to 2021, based on the current inventory
methodology, to indicate trends. In the period 1993 to 2004:
CO emissions have fallen and are predicted to continue to fall in future, mainly
due to increasing numbers of vehicles in the fleet with improved emissions control
equipment.
CO2 emissions have risen and are predicted to continue to rise in future, mainly
due to increased fuel consumption resulting from increased numbers of vehicles in
the region and increased vehicle kilometres travelled.
NOx emissions have risen slightly, mainly due to increased numbers of diesel
vehicles in the fleet, but are predicted to fall slightly in future as diesel emissions
control technology improves.
TP292 Auckland Air Emissions Inventory 2004Page iii
SO2 emissions have risen, mainly due to increased diesel fuel consumption
resulting from increased numbers of diesel vehicles, but are predicted to fall in
future as fuel sulphur levels continue to decrease.
PM10 and VOC emissions have fallen slightly, mainly due to a shift away from coal
and wood for both domestic heating and industrial use, and are predicted to fall in
future with fuel trends and technology improvements.
Further Work
There are other potentially significant sources of PM10 that are not estimated by the
current inventory, including secondary particulates, sea salt, and wind blown or re-
suspended dust. Estimation of these sources is uncertain. However, preliminary
investigations suggest that these sources could account for up to 20% of the total
ambient PM10 on days of high air pollution (calm days, with 24-hour concentrations
higher than 40µg m-3). Further work is necessary to validate assumptions in the existing
inventory and confirm key trends.
Key Conclusions
Ambient air concentrations of both PM10 and NOx in the Auckland region currently
exceed accepted health guidelines and standards.
From the inventory, the largest single contributors to annual emissions of PM10 are motor
vehicles (41%) and domestic heating (38%). For NOx emissions, the principal source is
motor vehicles (71%). Consequently, emissions management strategies that target
these sources will have the greatest impact on improving air quality in Auckland.
TP292 Auckland Air Emissions Inventory 2004Page iv TP292 Auckland Air Emissions Inventory 2004
Page 1
1 Introduction
This report summarises the results of the 2004 Auckland Air Emissions Inventory.
The inventory estimates emissions on a 3km x 3km grid basis for the entire study area
shown in Figure 1.1, and on a more detailed 1km x 1km grid for the urban area
highlighted. Emissions are estimated on an annual, daily (seasonal) and hourly basis.
Seasonal emissions are estimated for typical Summer (December-February), Autumn
(March-May), Winter (June-August) and Spring (September-November) days. Unless
stated otherwise, all reported results are for the entire inventory area (3km x 3km grid).
Figure 1.1
Auckland air emissions inventory study area showing the boundaries of the urban area chosen for finer (1km x 1km) resolution of emissions
study area
urban area
TP292 Auckland Air Emissions Inventory 2004Page 2
1.1 Background
An Auckland Air Emissions Inventory was first prepared in 1993 (ARC, 1997). An
upgrade commenced in 1998, which produced emissions estimates for 1993, 1998, 2011
and 2021 (EPAV, 2005). The upgrade is referred to in this report as “the 1998
inventory”. The 1998 inventory focused on improving estimates of the most significant
pollution sources identified in the 1993 inventory. Detailed analysis undertaken for the
1993 inventory was not repeated for the 1998 inventory where the source contributions
were small and/or the emissions would not have changed significantly. In such cases,
emissions were scaled up on the basis of some relevant measure such as population.
This update (referred to as “the 2004 inventory”) is based on the same methodology as
the 1998 inventory, however a number of assumptions have changed as detailed in
Table 1.1. 1998 and 2011 emissions estimates (calculated based on these new
assumptions) were interpolated to provide 2004 estimates.
Emissions estimates are presented for 1993, 2004, 2011 and 2021 based on the
methodology of the 1998 inventory and the new assumptions stated in Table 1.1.
Table 1.1
Comparison of assumptions made for the 2004 and 1998 emissions inventories
2004 Inventory 1998 Inventory Reason for Change Effect of Change 1
(versus 1998)
Total vehicle VKT are based on Regional fuel consumption Vehicle emissions
kilometres travelled outputs from the estimated from the VFM increased by 30%
(VKT) are based on Auckland Regional derived VKT is closer to
Ministry of Transport Transport model (ART) the actual fuel
estimates from the consumption recorded
Vehicle Fleet Model
(VFM)
Diesel vehicle exhaust All emissions factors Diesel vehicle exhaust is a Vehicle PM10
PM10 emissions factors are from the Ministry of significant contributor to emissions increased
have been adjusted Transport NZTER PM10, and it is likely that by 10%
(+15%) to attempt to database (MoT, 2000) gross emitters are not
account for the impact accounted for by the
of gross emitters NZTER emissions factors
used in this inventory
Re-suspended road Re-suspended road In a recent review, DEFRA Total PM10 emissions
dust is assumed to be dust is calculated concluded that re- reduced. (Re-
zero. It is according to USEPA suspended road dust an suspended road dust
recommended that the methodology important source, however accounted for
road dust contribution it is difficult to quantify with approximately 60% of
to PM10 should be any accuracy, and can all PM10 in the 1998
estimated based on result in double-counting inventory)
monitoring and
modelling.
1 Approximate change in mass emission based on 2004 emissions calculated with 1998 assumptions vs. 2004 emissions calculated with new
assumptions. The change is reported as a % change in the current, actual 2004 emissions if they had been calculated with the 1998
methodology
TP292 Auckland Air Emissions Inventory 2004Page 3
Table 1.1 continued
2004 Inventory 1998 Inventory Reason for Change Effect of Change 1
(versus 1998)
It is assumed that 15% It is assumed that 40% A recent review (DEFRA, Vehicle PM10
of TSP from vehicle of TSP from tyre wear 2004) estimates that emissions decrease
tyre wear is PM10 is PM10 between 1-15% of tyre by 20%
wear material is PM10
Emissions from petrol Emissions from petrol Updated and corrected VOC emissions from
storage at Wiri are storage are based on Wiri increased by 35%
estimated based on 1993 fuel consumption (approx 0.4% increase
current and projected and located at in total VOC)
regional fuel Freemans Bay tank
consumption farm
The seasonal profile The seasonal profile The seasonal profile for No effect on annual
for domestic wood and for domestic wood and domestic wood and coal emissions. Winter
coal is based on winter coal is based on winter usage was incorrect in the emissions increased
as June to August as July to September 1998 inventory by about 20% and
Autumn emissions
decreased. (Summer
and Spring
unchanged)
1.2 Pollutants
This inventory estimates air emissions of particles (TSP, PM10 and PM2.5), carbon
monoxide, oxides of nitrogen, volatile organic compounds, sulphur dioxide, and carbon
dioxide. The significance of these pollutants in the Auckland region is briefly described
in Table 1.2. Further information on ambient air pollutants can be found in the State of
the Auckland Region Report 2004 (ARC, 2004) and on the Ministry for the Environment
website (www.mfe.govt.nz).
1 Approximate change in mass emission based on 2004 emissions calculated with 1998 assumptions vs. 2004 emissions calculated with new
assumptions. The change is reported as a % change in the current, actual 2004 emissions if they had been calculated with the 1998
methodology.
TP292 Auckland Air Emissions Inventory 2004Page 4
Table 1.2
Key air pollutants in Auckland
Pollutant Significance for Auckland
Particles PM10 are tiny particles suspended in the air that are invisible to the human eye.
(TSP, PM10, PM2.5) PM10 are fine particles less than 10 microns in diameter, which are about 1/5th
the size of a human hair. These particles can affect health, especially in
asthmatics and people with heart and lung disease. Particles can carry
carcinogenic (i.e. cancer producing) material into the lungs. Fine particles can
increase hospital admissions and emergency department visits, school
absences, lost work days and restricted activity days. Studies show a correlation
between levels of fine particles and the number of people who die each year (the
mortality rate). Particles larger than 10 microns in diameter are unlikely to result
in health impacts but may cause nuisance effects. The finer (PM2.5) size fraction
is a subset of the PM10 size fraction and is particularly significant because of the
ability of these particles to penetrate the lungs.
Concentrations of PM10 measured in Auckland have exceeded both the NES of
50µg m-3 (24-hour average) and the ambient air quality guideline of 20µg m-3
(annual average) at urban monitoring sites. As PM10 is a “no safe threshold”
contaminant, adverse health effects are likely to occur at concentrations lower
than the standard and guideline levels.
CO Carbon monoxide (CO) interferes with the blood's ability to absorb and circulate
oxygen. This makes it relatively toxic. High levels of CO can affect people with
heart conditions such as angina and can impair co-ordination and attention.
Maximum CO concentrations are generally less than the NES at urban
monitoring sites in the region. Levels at roadside sites have dropped
significantly over recent years, but still may occasionally exceed ambient air
quality guidelines.
VOCs Volatile organic compounds (VOCs) are of concern because they contribute to
the formation of ozone in the atmosphere. VOCs also include air toxics (such as
formaldehyde and benzene), which can cause skin, throat and eye irritation,
headaches, nerve and organ damage, and increased risk of cancers and
premature death.
Limited monitoring of benzene in the Auckland region has demonstrated that
levels may exceed the ambient air quality guideline at roadside sites, but are
within the guideline in other areas.
Ozone Although ozone (O3) is a vital component of the upper atmosphere, at ground
level it is an unwanted toxic gas. Ozone causes runny eyes, nose and throat
irritations and breathing difficulties, especially for asthmatics. It also affects the
functioning of the heart. Like PM10, no safe threshold has been identified below
which effects of ozone do not occur.
Ozone is referred to as a secondary pollutant because it is not emitted directly
from typical pollution sources in the region. Ozone forms when NOx emissions
react in the presence of sunlight and VOCs. Maximum ozone concentrations are
close to the NES at ambient air quality monitoring sites within the region.
SO2 Sulphur dioxide (SO2) irritates the lungs, causing coughing, wheezing and
breathlessness. Asthmatics may suffer from reduced airflow to the lungs when
levels of SO2 exceed guideline values.
Concentrations of SO2 measured in the region are typically less than 33% of the
NES.
TP292 Auckland Air Emissions Inventory 2004Page 5
Table 1.2 continued
Pollutant Significance for Auckland
NOx and NO2 Nitrogen dioxide (NO2) can irritate the lungs, increase the susceptibility and
severity of asthma and lower resistance to infections such as the flu. It can also
affect vegetation and can significantly degrade visibility because it contributes to
the formation of brown hazes and smog.
NO2 concentrations are generally less than 66% of the NES at urban monitoring
sites in the region but regularly exceed the standard at roadside monitoring sites.
NO2 concentrations in Auckland have generally increased over the past decade.
NO2 together with other oxides of nitrogen (NOx) are also important contributors
to the formation of ozone.
CO2 Estimates of emissions of CO2 are included in the inventory to provide
information for greenhouse gas emission inventories.
National Environmental Standards for air quality (NES) were introduced by the Ministry
for the Environment in October 2004 (MfE, 2005a). These include ambient air quality
standards for carbon monoxide (CO), fine particles (PM10), nitrogen dioxide (NO2),
sulphur dioxide (SO2), and ozone (O3). In areas where the ambient air quality standards
are not met, the NES requires Regional Councils to take action. In particular, for any
airsheds that are likely to exceed the PM10 standard, and are gazetted, each Council is
required to develop an action plan in the form of a “straight line path” (SLiP) or a “curved
line path” (CLiP) to achieve compliance with the standard by September 2013 (MfE,
2005b).
Emissions estimates for all pollutants are presented in this report. However, the focus is
on PM10, because of the SLiP requirement. This report reviews and updates the
Auckland Regional Emissions Inventory to provide a starting point for development of
emissions projections to meet the SLiP. The information available to predict trends to
2013 is reviewed, and critical data gaps are identified.
TP292 Auckland Air Emissions Inventory 2004Page 6
1.3 Sources of Emissions
The inventory estimates emissions from significant sources, which are grouped into
transport, industrial and commercial, domestic and biogenic categories as follows:
Transport Industrial and Commercial
Motor vehicles Industry
Off-road vehicles Commercial and unallocated fuel
combustion (e.g. boilers)
Trains
Service stations
Aircraft
Surface coatings (e.g. paints)
Ships and boats
Aerosols
Bitumen (from road building)
Dry cleaning
Gas leakage
Domestic Biogenic (Natural)
Domestic fuel combustion NOx and VOC emissions from
(including wood, coal, and gas for vegetation and soils
heating)
Open burning of rubbish
Lawn mowers
This report summarises the emissions estimates, and briefly describes the methodology
for estimating the emissions from all sources. However, the focus is primarily on motor
vehicles and domestic heating because the 1993 and 1998 emissions inventories
identified these as the main sources of PM10 in the region.
1.4 Results for Ambient Air Pollutants
Figure 1.2 illustrates the contributions of various sources to total annual emissions of
each ambient pollutant over the entire study area in 2004. A full summary of results is
included in Appendix 1.
The emissions inventory estimates that transport emissions account for 78% of the total
mass of all ambient pollutants (excluding CO2) resulting from anthropogenic (man-made)
sources.
For annual anthropogenic emissions of PM10, the inventory estimates that 47% is from
transport, 39% from domestic sources and 14% from industrial sources across the entire
Auckland region.
TP292 Auckland Air Emissions Inventory 2004Page 7
Figure 1.2
Annual ambient air pollutant emissions for the Auckland region in 2004
PM 10 Volatile Organic Compounds
(total = 5.9 kt/annum) (total = 64 kt/annum)
Biogenic Domestic
13% 10%
Domestic
39%
Transport Industrial
47% 26%
Transport
Industrial
51%
14%
Nitrogen Oxides Sulphur Dioxide
(total = 35 kt/annum) (total = 4 kt/annum)
Domestic
Domestic 3%
Biogenic 1% Industrial
3% 13%
Industrial
32%
Transport
65%
Transport
83%
Carbon Monoxide Total Anthropogenic Emissions of PM 10,
(total = 171 kt/annum) VOC, NOx, SO2 and CO by mass
(total = 271 kt/annum)
Domestic
Domestic 12%
13%
Industrial Industrial
2% 10%
Transport
Transport 78%
85%
TP292 Auckland Air Emissions Inventory 2004Page 8
It should be noted that there are additional (and potentially significant) sources of PM10
emissions that have not been estimated by the inventory. These include:
natural sources, such as sea salt, bush fires and wind blown dust;
road dust generated by abrasion of the road surface and re-suspension;
particles formed in the atmosphere when primary pollutants react producing
secondary particulate
The likely contribution of these sources to ambient PM10 is discussed in the
Unaccounted Emissions section of this report.
1.5 Results for CO2
Figure 1.3
Annual CO2 emissions for the Auckland region in 2004
The emissions inventory estimates that 48%
Carbon Dioxide
of CO2 emissions are from transport, 46%
(total = 8,930 kt/annum)
from industry and 6% from domestic
Domestic
6%
sources (see Figure 1.3). Other important
greenhouse gases include methane and
nitrous oxide, however these are not
estimated in this inventory.
Transport
48% Greenhouse gas emissions are monitored
Industrial
46% and managed at a national level by the
Ministry for the Environment.
TP292 Auckland Air Emissions Inventory 2004Page 9
1.6 Results for PM10 in the Urban Area
Figure 1.4
Annual PM10 emissions for the Auckland urban area only in 2004
Transport is estimated to contribute 51% of
PM10 Urban Area
PM10 on an annual basis in the urban area (see
(total = 4.9 kt/annum)
Figure 1.4).
This proportion is higher than that estimated for
Domestic
transport across the entire emissions inventory
41% study area (47%), because of large industrial
Transport
51% sources located outside the urban area.
Industrial
8%
1.7 Results by Season
Annual emissions estimates indicate the likely contribution of sources to ambient air
pollution over an entire year. The emissions inventory includes seasonal and hourly
emissions data so that emissions can be predicted over shorter averaging periods, and
compared with ambient air quality guidelines.
There is significant seasonal variation in PM10 emissions because of domestic heating in
winter. This is discussed further in Section 2.
TP292 Auckland Air Emissions Inventory 2004Page 10
2 Domestic Emissions
2.1 Domestic Sources
Figure 2.1
Annual PM10 emissions for the Auckland region in 2004
Domestic sources include fuel burning
PM 10
(primarily for heating), lawnmowing and open
(total = 5.9 kt/annum)
burning of rubbish. These sources combined
are estimated to contribute 39% of PM10 on
an annual basis (see Figure 2.1).
Domestic
39% However, the relative contribution of domestic
Transport
47% emissions to other sources varies significantly
with season peaking at 64% in winter (June-
August) but falling to only 2% in summer
(December-February) as shown in Figure 2.2.
Industrial
14%
Figure 2.2
Seasonal variation in typical daily PM10 emissions in 2004. Note: winter weekday emissions are nearly three times those of summer
PM 10 Winter Weekday
PM10 Summer Weekday (total = 29 tonnes/day)
(total = 10 tonnes/day)
Domestic Transport
2% 27%
Industrial
23%
Transport
Industrial
75% Domestic
9%
64%
The majority of domestic PM10 comes from home heating with combustion of solid fuels
– wood and coal – accounting for 95% of all annual emissions (see Figure 2.3). Across
the whole of Auckland, around 28% of households use wood burners (109,000
TP292 Auckland Air Emissions Inventory 2004Page 11
households), 11% use open fires (42,000 households) and 3% use multifuel burners
(11,000 households) for domestic heating 2. Figure 2.4 illustrates the contribution of
various heating methods to total domestic heating PM10 emissions.
Figure 2.3 Figure 2.4
Relative contribution of various sources to annual domestic Relative contribution of various methods to annual home heating
PM10 emissions in 2004 PM10 emissions in 2004
Contribution of Heating Methods to PM 10
Domestic Sources of PM10 (2004)
Emissions
coal Multi-fuel - coal Gas
14% gas 1%
law n mow ing 5%
0.4% Open fire - wood
1%
Multi-fuel - wood 14%
LPG 5%
0.5%
Post 1997 burner Open fire - coal
rubbish 12% 9%
burning
4%
1991-1996 burner
14%
Pre 1991 burner
w ood
40%
81%
Figure 2.5 shows the seasonal variation in domestic heating emissions for wood burning,
with greater than 80% of PM10 emissions occurring in the winter months of June through
August.
Figure 2.5
Seasonal variation in domestic wood burning emissions
Seasonal Variation of Domestic Heating Emissions
(wood burning)
percentage of emissions from wood burning
90.0%
80.0%
70.0%
60.0%
50.0%
40.0%
30.0%
20.0%
10.0%
0.0%
Summer (Dec-Feb) Autumn (Mar-May) Winter (Jun-Aug) Spring (Sep-Nov)
2 Households using multiple methods are included more than once.
TP292 Auckland Air Emissions Inventory 2004Page 12
There is also significant geographical variation in domestic heating emissions (see
Figure 2.6). The spatial distribution shown is based on the results of the domestic
heating survey as well as census information.
Figure 2.6
Spatial distribution of domestic heating emissions.
* Note: The “proportion” refers to contribution of each 3km grid cell to the regional total.
Size of 3x3km grid cell
Proportion of total
0.000 - 0.001 0.0 - 0.1%
0.001 - 0.004 0.1 - 0.4%
0.004 - 0.008 0.4 - 0.8%
0.008 - 0.014 0.8 - 1.4%
0.014 - 0.030 1.4 - 3.0%
2.2 Domestic Heating Emissions Estimation
Domestic heating emissions are calculated from emissions factors (g/kg of fuel burnt),
and estimates of the amount of fuel burnt per household. The emissions factors used
are shown in Table 2.1.
TP292 Auckland Air Emissions Inventory 2004Page 13
Table 2.1
Domestic heating emissions factors and average daily fuel use per appliance
Appliance Type PM10 CO NOx SO2 VOC CO2 Average Daily
Fuel Use (kg)
Open fire - wood (g/kg) 15 120 1.6 0.2 30 1,600 9
Open fire - coal (g/kg) 33 60 1.5 9.0 15 2,600 11
Pre 1991 woodburner (g/kg) 13 130 0.5 0.2 39 1,600 19
91-96 woodburner (g/kg) 7 70 0.5 0.2 21 1,800 17
Post 1997 woodburner (g/kg) 6 60 0.5 0.2 15 1,800 19
Multifuel – wood (g/kg) 13 130 0.5 0.2 39 1,600 11
Multifuel – coal 3 (g/kg) 28 120 1.2 9.0 15 2,600 8
Oil (g/kg) 0.9 0.6 2.2 3.8 0.25 3,200 8
LPG (g/kg) 0.6 0.18 1.3 0.00 0.2 2,500 1
Gas (t/106m3 or g/m3) 0.18 0.64 1.5 0.01 0.12 1,920 n/a 4
Emissions factors for gas combustion are based on USEPA methodology as outlined in
the 1993 inventory (ARC, 1997). Emissions factors for open fires are the same as those
used in the 1996 Christchurch inventory (CRC, 1997). All other emissions factors are as
recommended by Wilton (2002). These are based on emissions factors adopted in other
North Island inventories, and are similar to those developed for the 1996 Christchurch
inventory.
Updated emissions factors, based on testing undertaken in New Zealand, have been
recommended by Wilton (2002) for open fires, and oil and gas burners. Emissions
testing to determine real world emissions factors for other types of burners in New
Zealand is currently being undertaken. When this information becomes available, all
domestic heating emissions factors will be reviewed and updated.
Estimated wood, coal and LPG usage rates are based on the results of a domestic
heating emissions inventory completed in 2001 (Wilton, 2002). Data on heating methods
and fuels were obtained via a telephone survey conducted during winter 2002. The total
sample size was 1,764 giving a statistical sampling uncertainty of 7.5%. The survey
determined the fuel usage as well as the number of households using different heating
methods at different times of year. To estimate fuel consumption, households were
asked to estimate their daily fuel use in buckets of coal, or number of split logs put on the
fire. These data were converted to weights based on the assumption that a split log
weighs 1.4kg and a bucket of coal weighs 9kg. Gas consumption figures are based on
sales data.
Estimated daily fuel consumption per appliance is included in Table 2.1. Annual fuel
consumption figures are shown in Table 2.2. Projected fuel consumption rates are
based on the results of a domestic heating emissions projection study (Wilton, 2004).
3 includes potbelly, incinerator, coal range and any enclosed burner that is used to burn coal.
4 gas consumption was calculated based on measured sales figures. A daily consumption of 1kg/appliance was estimated based on survey
results, however this figure was not used in the inventory.
TP292 Auckland Air Emissions Inventory 2004Page 14
Table 2.2
Annual domestic fuel consumption
Fuel 1998 2004 2011 2021
Wood (kt/year) 197 183 167 151
Coal (kt/year) 13.4 10.7 7.5 4.5
6 3
Natural Gas (10 m /year) 35.6 48.8 60.0 75.9
LPG (kt/year) 14.6 18.6 23.4 29.6
2.2.1 Baseline emission projections for domestic heating
The baseline projections for domestic heating emissions in 2011 and 2021 predict a
modest reduction in domestic heating emissions overall, but solely due to a predicted
decline in the use of wood and coal burners (as reported in Wilton, 2004). No allowance
has been made for improvements in average domestic heating emissions factors over
time. The promulgation of a National Environmental Standard for woodburners will result
in improved average emissions factors over time. However the impact of the standard is
highly dependent on the woodburner replacement rate, for which very little regional data
exist, and so it is not incorporated into the baseline calculations. Further discussion is
covered in Section 5 (Trends).
2.3 Emissions Estimation for Other Domestic Sources
Table 2.3 summarises the factors used to estimate emissions from other domestic
sources.
Table 2.3
Emissions factors for open burning and lawn mowing
Pollutant Open Burning 2-stroke Lawnmower 4-stroke Lawnmower
(kg/t) (g/hr) (g/hr)
CO 42 731 489
CO2 1,700 738 890
NOx 3 1.45 4.85
SO2 0.5 0.062 0.036
TSP 8 7.85 0.518
VOC 15 294 39.7
Emissions from open burning of rubbish were estimated in 1993 based on the results of
a domestic survey. Rubbish burning was estimated as 15.4kg/year per person.
Emissions factors for rubbish burning were based on USEPA emissions factors for open
burning of municipal refuse, except for CO2 which was based on the domestic wood
combustion emissions factor. Most open burning has been banned in the Auckland
Region through regulations in the Proposed Regional Plan: Air Land and Water, as well
as the National Environmental Standard for air (MfE, 2005a). To reflect the likely effect
of these regulations, it has been assumed that emissions from open burning reduce 66%
TP292 Auckland Air Emissions Inventory 2004Page 15
by 2011. This is based on the observed effectiveness of burning restrictions in
Australian cities.
Lawn mowing emissions are also estimated based on the results of the 1993 domestic
questionnaire. Per capita lawnmowing time was estimated as 4.23 hours per year per
person. Emissions factors for lawnmowers are based on Australian data. Based on
information from retailers, it was estimated that 40% of lawnmowers were 2-stroke in
1998, reducing to 10% by 2021. Lawnmower emissions have been scaled up according
to population growth.
TP292 Auckland Air Emissions Inventory 2004Page 16
3 Transport Emissions
3.1 Transport Sources
Figure 3.1
Annual PM10 emissions across the Auckland region in 2004
Transport sources include motor
PM10 vehicles, off-road vehicles,
(total = 5.9 kt/annum) trains, aircraft, ships and boats,
and emissions from bitumen
Transport used in road construction.
(diesel exhaust)
30% Domestic Figure 3.1 shows that transport
39%
sources are estimated to
contribute 47% of PM10
emissions on an annual basis,
with 88% of these emissions
Transport
(other) coming from motor vehicles, as
17% shown by Figure 3.2.
Industrial
14%
Figure 3.2 Figure 3.3
Relative contribution of various sources to annual transport PM10 emissions Sources of annual motor vehicle PM10 emissions
Transport Sources of PM10 (2004) Motor Vehicle PM10 Emissions (2004)
Aircraft petrol vehicle
Ships and boats Trains tyre and brake
2%
7% 1% w ear
11%
petrol vehicle
Off-road exhaust
1% 7%
diesel vehicle
tyre and brake
w ear
9%
diesel vehicle
exhaust
Motor vehicles. 73%
88%
Figure 3.3 breaks down the motor vehicle emissions even further. The largest fraction
(73% of motor vehicle PM10 emissions) comes from diesel exhaust, which contributes
30% of the total annual PM10 emissions across the region by itself.
TP292 Auckland Air Emissions Inventory 2004Page 17
More than 90% of all motor vehicle travel in the Auckland Region takes place within the
urban area as highlighted by the spatial distribution of VKT shown in Figure 3.4. In
addition, motor vehicles are responsible for a higher proportion of transport emissions in
the urban area (93% versus 88% across the region) due to the majority of shipping
emissions occurring at sea.
Figure 3.4
Spatial allocation of VKT across the Auckland region in 2004
Total annual VKT
0 - 20,000,000
20,000,000 - 50,000,000
50,000,000 - 105,000,000
105,000,000 - 215,000,000
215,000,000 - 500,000,000
3.2 Motor Vehicle Emissions Estimation
Motor vehicle emissions are calculated from emissions factors (g of pollutant per km
driven) developed for the regional vehicle fleet and estimates of vehicle travel (km per
year).
3.2.1 Emissions factors
Single vehicle emissions factors in g/km for CO, NOx, TSP and VOC were obtained from
the New Zealand Traffic Emissions Rates database (MoT, 2000). The database
TP292 Auckland Air Emissions Inventory 2004Page 18
provides emissions factors for specified vehicle types 5, under different driving conditions
and road types for a range of pollutants. The database provides a fleet average
emission factor for any given year and any given combination of vehicle type/driving
condition/road type. There are approximately 3000 combinations of pollutant/vehicle
type/driving condition/road type for each year.
Diesel vehicle emissions factors
Diesel vehicle PM10 emissions have been adjusted to attempt to account for the impact
of “gross emitters”. Other pollutants and vehicle types were not considered at this stage,
because of the current focus on PM10. The impact of gross emitters has been estimated
for diesel buses (EFRU, 2004). This study estimates a reduction in PM10 emissions of
12% in 2003, and 17% in 2011, for an inspection and maintenance programme that
identifies and repairs the worst 20% of buses. The NZTER emissions factors do not
account for the proportion of poorly tuned and marginally tuned vehicles in the fleet
(SKM, 2003). In the absence of better information, diesel exhaust PM10 emissions
factors have been increased by 15% for the 2004 inventory update.
CO2 emissions factors
Emission factors for CO2 were calculated from fuel consumption data. Fuel consumption
data for most vehicle, road and driving types were based on data derived from the
Ministry of Transport’s Vehicle Fleet Model (VFM). Fuel consumption factors in later
years were adjusted to account for the fleet becoming more efficient. Australian data
(NGGI, 1998) were used to fill any gaps to produce fuel consumption figures for all years
in L/km (MJ/km for CNG) by vehicle, fuel, road and congestion type.
SO2 emissions factors
SO2 emission factors were also based on the fuel consumption data. Fuel based
emissions factors were derived based on New Zealand fuel sulphur contents using the
methodology described in the EMEP/CONNAIR Emissions Inventory Guidebook
(Campbell and Moncrieff, 2004) and are summarised in Table 3.1.
Table 3.1
SO2 emissions factors for various motor vehicle fuels
Fuel 1993 1998 2011 2021
Petrol (kg SO2/t fuel) 6 0.7 0.3 0.08 0.01
Diesel (kg SO2/t fuel)6 5.0 4.0 0.02 0.01
LPG (kg SO2/t fuel) 0.026 0.026 0.026 0.026
CNG (mg SO2/m3 gas) 40 40 40 40
5 Emission factors for petrol HCVs and buses were not included in the MoT database. For these vehicles, emission factors for petrol LCVs were
multiplied by the ratios of the corresponding Australian emission factors.
6 Note SO2 factors have been based upon a petrol sulphur content of 40ppm (‘Euro 4’-like specification less manufacturing margin allowance)
and 7ppm for diesel (possible 2011 diesel specification less manufacturing margin allowance) for 2011 and a maximum 5ppm sulphur
specification for both petrol and diesel for 2021.
TP292 Auckland Air Emissions Inventory 2004Page 19
Calculated fleet weighted exhaust emissions factors
For the Auckland emissions inventory, vehicle kilometres travelled were estimated for
each year, road type and congestion level as described in the following sections. The
fleet weighted emissions factors calculated for 2004 are shown in Table 3.2.
Table 3.2
Fleet weighted exhaust emissions factors for various road types and driving conditions in 2004
Road Type Congestion 2004 Fleet-Weighted Exhaust Emission Factors (g/km)
Level CO CO2 NOx SO2 PM10 7 VOC
Central Free 7.8 326 2.12 0.097 0.158 1.16
Urban Interrupted 12.8 492 2.74 0.132 0.213 1.61
Congested 24.3 684 3.32 0.176 0.314 4.03
Cold Start 43.7 693 2.83 0.169 0.332 4.96
Motorway Free 3.82 261 2.54 0.080 0.182 0.53
Interrupted 5.1 239 1.77 0.072 0.119 0.57
Congested 7.9 287 1.82 0.083 0.148 0.99
Cold Start 22.8 330 1.85 0.091 0.173 3.92
Suburban Free 6.6 310 2.03 0.087 0.138 1.06
Interrupted 10.2 355 2.20 0.097 0.163 1.24
Congested 14.8 428 2.32 0.119 0.230 1.95
Cold Start 33.3 498 2.47 0.124 0.261 5.40
Fleet Weighted Average 11.8 344 2.17 0.095 0.171 1.64
Non-exhaust emissions factors
Evaporative VOC, brake and tyre wear emissions factors were derived for New Zealand
conditions using the VFM (see Tables 3.3 to 3.5). It was assumed that 40% of brake
wear TSP is PM10 and 15% of tyre wear TSP is PM10.
Table 3.3
Evaporative VOC emissions factors for different petrol vehicle types for various years (irrespective of road type)
Vehicle Type Congestion Evaporative VOC (g/km)
Level 1993 1998 2011 2021
Petrol Car Free 0.50 0.50 0.13 0.08
Interrupted 2.80 2.60 0.30 0.10
Congested 5.00 5.00 0.40 0.15
Cold Start 0.30 0.20 0.10 0.04
Petrol LCV 8 Free 0.80 0.80 0.20 0.10
Interrupted 4.00 4.00 0.40 0.12
Congested 6.00 6.00 0.50 0.20
Cold Start 0.50 0.50 0.14 0.04
7 exhaust particulate emission factors are reported as TSP in NZTER. The emissions inventory assumes that 100% of TSP is PM10.
8 In the absence of other data, petrol HCVs and buses were assumed to have the same evaporative VOC emissions as petrol LCVs
TP292 Auckland Air Emissions Inventory 2004Page 20
Table 3.4
Tyre wear PM10 emissions factors for different vehicle types and various congestion levels (irrespective of year)
Vehicle Type Tyre Wear PM10 (g/km)
Free Interrupted Congested Cold Start
Car 0.009 0.018 0.036 0.018
LCV 0.011 0.023 0.045 0.023
HCV (small) 0.019 0.038 0.075 0.038
HCV (medium) 0.028 0.056 0.113 0.057
HCV (large) 0.126 0.252 0.504 0.254
Bus (medium) 0.027 0.054 0.108 0.054
Bus (large) 0.105 0.210 0.420 0.212
Motorcycle 0.005 0.009 0.018 0.009
Table 3.5
Brake wear PM10 emissions factors for different vehicle types and various congestion levels (irrespective of year)
Vehicle Type Brake Wear PM10 (g/km)
Free Interrupted Congested Cold Start
Car 0.004 0.013 0.017 0.010
LCV 0.006 0.018 0.024 0.014
HCV (small) 0.008 0.026 0.034 0.020
HCV (medium) 0.010 0.030 0.040 0.023
HCV (large) 0.016 0.048 0.064 0.037
Bus (medium) 0.010 0.028 0.038 0.022
Bus (large) 0.014 0.040 0.054 0.031
Motorcycle 0.002 0.004 0.008 0.004
3.2.2 Vehicle type
The fleet profile (vehicle type) is based on Ministry of Transport (MoT) estimates of
nationwide vehicle kilometres travelled by each vehicle type generated from their Vehicle
Fleet Model (VFM) (see Table 3.6).
VFM estimates current vehicle utilisation rates based on actual registration information,
with future utilisation rates based on projected regional growth. Updated figures for
vehicle utilisation rates from VFM were provided in 2004.
TP292 Auckland Air Emissions Inventory 2004Page 21
Table 3.6
Proportion of vehicle kilometres travelled by each vehicle type in Auckland
Vehicle Type Fuel Type Proportion of VKT
1993 2004 2011 2021
Car petrol 72.77% 72.22% 71.87% 71.93%
Car diesel 4.07% 4.71% 5.33% 5.14%
Car CNG 0.01% 0.01% 0.01% 0.01%
Car LPG 0.03% 0.03% 0.03% 0.03%
LCV 9 petrol 8.75% 6.99% 5.37% 4.30%
LCV diesel 5.31% 7.00% 8.59% 9.67%
LCV CNG 0.00% 0.01% 0.01% 0.01%
LCV LPG 0.01% 0.01% 0.01% 0.01%
HCV (small) 10 petrol 0.28% 0.22% 0.16% 0.11%
HCV (medium) petrol 0.14% 0.11% 0.08% 0.04%
HCV (large) petrol 0.11% 0.08% 0.05% 0.03%
HCV (small) diesel 3.10% 2.78% 2.49% 2.10%
HCV (medium) diesel 1.04% 1.00% 0.96% 0.89%
HCV (large) diesel 3.20% 3.51% 3.81% 4.55%
HCV (small) CNG 0.02% 0.02% 0.02% 0.01%
HCV (medium) CNG 0.01% 0.01% 0.01% 0.01%
HCV (large) CNG 0.00% 0.00% 0.00% 0.00%
HCV (small) LPG 0.02% 0.02% 0.01% 0.01%
HCV (medium) LPG 0.01% 0.01% 0.01% 0.01%
HCV (large) LPG 0.01% 0.01% 0.01% 0.01%
Bus (medium) 11 petrol 0.05% 0.04% 0.03% 0.01%
Bus (large) petrol 0.01% 0.01% 0.01% 0.01%
Bus (medium) diesel 0.19% 0.20% 0.20% 0.24%
Bus (large) diesel 0.46% 0.64% 0.59% 0.52%
Bus (medium) CNG 0.00% 0.00% 0.00% 0.00%
Bus (large) CNG 0.00% 0.00% 0.00% 0.00%
Bus (medium) LPG 0.01% 0.01% 0.01% 0.01%
Bus (large) LPG 0.00% 0.00% 0.00% 0.00%
Motorcycle petrol 0.38% 0.35% 0.32% 0.31%
VKT Total (millions of km) 8,840 11,400 13,100 15,800
3.2.3 Vehicle kilometres travelled
Estimates of total vehicle kilometres travelled (VKT) in the region are also based on
MoT’s VFM (Campbell and Moncrieff, 2004)
Vehicle kilometres travelled (VKT) were estimated in the 1998 emissions inventory
based on the Auckland Regional Transport model (ART). The peak flows predicted by
the ART model were scaled up to provide daily and annual VKT estimates. The VFM
estimates are significantly higher than the ART derived estimates. The VFM estimates
are based on vehicle registration information, including odometer readings. The ART
model is a strategic traffic demand model, which is calibrated to generate demands from
the key drivers of travel, for example land use. The main aims of this model are to allow
high level evaluation of policy alternatives and to produce travel demands for input into
9
Light commercial vehicle. Includes light bus and small bus categories from the Vehicle Fleet Model.
10 Heavy commercial vehicle –small:3.5-7.5 t medium: 7.5-12.0 t large:>12.0 t
11 Bus –medium:12.0 t
TP292 Auckland Air Emissions Inventory 2004Page 22
more detailed models. The model provides traffic data for three separate 2-hour time
periods: AM peak; midday; and PM peak. The emissions inventory requires daily and
annual estimates of VKT, which were estimated for the 1998 inventory from the 7-9am
peak results. There is a high level of uncertainty in scaling up to an annual estimate
from one modelled ‘typical’ 2 hour peak result. It is considered likely that the VFM
results will provide a better estimate of total annual VKT.
To check the likely accuracy of VKT from ART and VFM, the VKT have been used to
calculate fuel consumption. The VKT totals derived from ART as well as the MoT’s
VFM-derived VKT have been extrapolated to estimate 2004 VKT. Regional fuel
consumption was then estimated using VFM fuel consumption factors and the vehicle
profile described above. The VFM-derived VKT result in a much better estimate of
regional fuel consumption (see Table 3.7). Actual fuel consumption is a reliable
measure of vehicle activity, therefore it is considered that the VFM-derived VKT are likely
to be more realistic.
Table 3.7
Comparison of estimated annual fuel consumption based on ART and VFM derived VKT versus actual fuel consumption in Auckland
Fuel Type Estimated Consumption Actual Consumption
(ML/annum) ART (2004) VFM (2004) (2002)
Petrol 816 1079 1050
Diesel 397 525 450
The 2004 emissions inventory uses VFM-derived VKT totals as shown in Table 3.8 12.
The ART model outputs are used to provide the gridded spatial distribution data for VKT.
Different spatial distributions are used for each road/congestion/year combination.
Traffic counts were used to estimate diurnal variation. Spatial and diurnal data were not
updated for the 2004 emissions inventory.
12 VFM derived VKT were supplied for 2001, 2002, 2011, and 2021 (Campbell and Moncrieff, 2004). These VKT were back extrapolated to
estimate 1993 VKT, and interpolated to estimate 2004 VKT.
TP292 Auckland Air Emissions Inventory 2004Page 23
Table 3.8
VFM derived annual VKT used in emissions inventory
VKT (millions of km)
Free Flow Interrupted Congested Cold Start Total
1993
Central Urban 44 206 31 63 344
Motorway 784 1,780 299 289 3,150
Suburban 874 3,050 515 910 5,350
8,840
2004
Central Urban 44 272 53 74 443
Motorway 1,000 2,150 398 388 3,940
Suburban 1,020 4,090 735 1,200 7,040
11,400
2011
Central Urban 46 320 63 88 517
Motorway 1,130 2,390 460 449 4,430
Suburban 1,090 4,800 901 1,390 8,180
13,100
2021
Central Urban 46 396 82 107 631
Motorway 1,260 2,790 567 549 5,170
Suburban 1,170 5,940 1,190 1,700 9,990
15,800
3.3 Emissions Estimation for Other Transport Sources
Emissions from marine pleasure craft, commercial shipping, rail and off-road vehicles
have been estimated.
Estimates of shipping activity were obtained from ports of Auckland, and rail activity from
ARC. Marine pleasure craft activity estimates were based on registration data and the
results of the 1993 domestic survey. Off-road vehicle usage was estimated on a per
capita basis based on methodology recommended for Australian inventories. Aircraft
emissions were based on aircraft movements in 1998 and projections supplied by
Auckland International Airport Limited.
Emissions factors for rail, off-road vehicles and pleasure craft have been estimated on a
per capita basis (see Table 3.9). Emissions from these sources are projected to
increase in proportion to population growth.
TP292 Auckland Air Emissions Inventory 2004Page 24
Table 3.9
Population based emissions factors for pleasure craft, off-road vehicles and rail
Pleasure Craft Off-road Vehicles Rail
Pollutant
(kg/yr per person) (kg/yr per person) (kg/yr per person)
CO 1.78 4.49 0.153
CO2 20.4 35.1 24.6
NOx 0.149 0.640 0.495
SO2 0.013 0.0231 0.051
TSP 0.0086 0.0127 0.031
VOC 0.49 0.502 0.148
Emissions factors for shipping and aviation were derived from a variety of sources (see
Table 3.10). Australian emissions factors are used for for commercial shipping.
Emissions from aviation were estimated in 1993 based on USEPA methodologies. An
emissions factor per aircraft movement is based on 1993 emissions.
Table 3.10
Emissions factors for shipping and aviation
Pollutant Shipping Shipping Aviation
Main Engine Auxiliary Engine All Types
(kg/hr) (kg/hr) (kg/aircraft movement)
CO 13.5 1.19 9.68
CO2 8040 430 1160
NOx 167 6.66 5.36
SO2 127 5.66 0.356
TSP 16.8 0.9 0.430
VOC 3.41 0.436 3.48
TP292 Auckland Air Emissions Inventory 2004Page 25
4 Industrial Emissions
4.1 Industrial Sources
This category includes the most significant industrial emitters in the region, with air
emissions calculated for manufacturing processes as well as fuel combustion activities
undertaken on site. Companies are listed according to industry type in Appendix 2,.
As well as significant industrial sources, this source category includes unallocated fuel
combustion which refers to emissions resulting from small scale but widespread sources
(such boilers used for heating schools and greenhouses) and commercial sources of
VOC emissions (service stations, aerosol, dry cleaning, gas leakage, and surface
coating). The commercial VOC sources account for 76% of the total industrial VOC
emissions.
The contribution of industry to total emissions is very dependent on the spatial
boundaries considered. For the entire region, the inventory estimates that 14% of
annual PM10 emissions come from industrial sources (see Figure 4.1). However, this
fraction reduces to 8% for annual emissions in the urban area (see Figure 4.2) due to a
number of significant industrial sources being located outside the 1km x 1km grid limits.
Figure 4.1 Figure 4.2
Annual PM10 emissions for the Auckland region in 2004 Annual PM10 emissions for the Auckland urban area only in 2004
PM 10 PM 10 Urban Area
(total = 5.9 kt/annum) (total = 4.9 kt/annum)
Domestic
39% Domestic
Transport 41%
47%
Transport
51%
Industrial
14% Industrial
8%
Figures 4.3 and 4.4 show the breakdown of industry types for region-wide and urban
area only emissions respectively. Facilities involved in metal products and non-metallic
products are responsible for the majority of industrial PM10 emissions regardless of the
area under consideration.
TP292 Auckland Air Emissions Inventory 2004Page 26
Figure 4.3 Figure 4.4
Industrial sources of PM10 Industrial sources of PM10 in the urban area
Industrial Sources of PM10 (2004) Industrial Sources of PM10 (Urban, 2004)
(total = 810 t/annum) (total =399 t/annum)
Unaccounted
Unaccounted
Fuel
Fuel
Other 8%
4% Other Metal
6%
8% Products
Quarries 29%
13% Quarries
9%
Metal
Products
Non-Metallic 56%
Products
21% Non-Metallic
Products
46%
Combustion emissions from industry were estimated to provide information for source
apportionment studies. In the urban area it is estimated that 33% of industrial PM10
emissions are from combustion sources.
4.2 Industrial Emissions Estimation
Industrial emissions estimates are based on questionnaires completed by industry, as
well as ARC resource consent information and USEPA emissions factors. Where stack
test data were available, these were used in preference to literature emission rates.
Emissions information for some sources has not been updated since 1993, however,
most of the significant sources were updated in 2001.
Unaccounted fuel includes emissions from coal combustion by schools and by
horticulture (for greenhouse heating). Coal consumption figures were based on
estimates provided by all coal suppliers in the region. Consumption was estimated as
6,000 tonnes/annum for horticulture and 1,800 tonnes/annum for schools This category
also includes commercial gas combustion. Regional gas consumption figures were
based on accurate regional sales information.
For future years it is assumed that industrial emissions do not change, unless the
industry predicted a change of emissions in the industrial questionnaire.
TP292 Auckland Air Emissions Inventory 2004Page 27
5 Trends
The emissions inventory includes emissions projections to 2011 and 2021. Annual
emissions estimates for all years are summarised in Appendix 1.3. The predicted trends
are illustrated in Figures 5.1 and 5.2. The emissions factors and assumptions adopted
for these ‘baseline predictions’ are discussed briefly in previous sections. Key
assumptions for the baseline projections are:
Motor vehicle emissions are based on VKT and fleet projections from the Ministry of
Transport vehicle fleet model (VFM), and NZTER emissions factors.
Domestic heating emissions projections assume that there is no improvement in
average emissions factors, but that use of coal and wood declines as open fires and
fireplaces are replaced.
These projections need to be updated to reflect a number of changes that have occurred
including:
Changes to national fuel specifications and vehicle emissions regulations that have
occurred since the NZTER emissions factors were published in 2000.
Promulgation of a National Environmental Standard for woodburners, which should
ensure that average emissions factors from domestic heating improve over time.
Domestic heating and vehicle emissions projections are discussed further in the
following sections.
Figure 5.1
Predicted baseline trends for PM10
Predicted Baseline Trend (PM10)
7000
6000
5000
Emissions (t/yr)
4000 Transport
Industrial
3000 Domestic
2000
1000
0
1993 2004 2011 2021
TP292 Auckland Air Emissions Inventory 2004Page 28
Figure 5.2
Predicted baseline trends for all pollutants
CO SO2
300 12000 12
NOX TSP
VOC PM10
250 CO2 10000 10 PM2.5
CO, NOx, VOC (kt/yr) .
200 8000 8
.
CO (kt/yr)
6
kt/yr
150 6000
100 4000 4
50 2000 2
0 0 0
1993 2004 2011 2021 1993 2004 2011 2021
5.1 Overall Trends
The overall trends, using the corrected emissions for 1993 (based on the 2004
methodology) and extrapolated to 2021, are shown in Figure 5.3. These data are
normalised to the 2004 emissions to highlight the relative trends. In the period 1993 to
2004:
CO emissions have fallen and are predicted to continue to fall in future, mainly
due to increasing numbers of vehicles in the fleet with improved emissions control
equipment.
CO2 emissions have risen and are predicted to continue to rise in future, mainly
due to increased fuel consumption resulting from increased numbers of vehicles in
the region and increased vehicle kilometres travelled.
NOx emissions have risen slightly, mainly due to increased numbers of diesel
vehicles in the fleet, but are predicted to fall slightly in future as diesel emissions
control technology improves.
SO2 emissions have risen, mainly due to increased diesel fuel consumption
resulting from increased numbers of diesel vehicles, but are predicted to fall in
future as fuel sulphur levels continue to decrease.
PM10 and VOC emissions have fallen slightly, mainly due to a shift away from coal
and wood for both domestic heating and industrial use, and are predicted to fall in
future with fuel trends and technology improvements.
TP292 Auckland Air Emissions Inventory 2004Page 29
Figure 5.3
Overall emissions trends (normalised to 2004 emissions)
Auckland Region Emissions Trends
1.5
CO
1.4
1.3
1.2 VOC
CO2
1.1
PM10
1 SO2
Ratio to 2004 Emission
0.9 NOx
NOx
PM10
0.8
VOC
0.7 SO2
CO2
0.6
CO
0.5
0.4
0.3
0.2
0.1
0
1990 2000 2010 2020 2030
Year
5.2 Trends in Domestic Heating Emissions
The baseline projections for domestic heating emissions assume no improvement in
domestic heating emissions factors over time. A modest reduction in domestic heating
emissions is predicted, due to a predicted decline in the use of wood and coal burners.
A range of possible scenarios for reduction of domestic heating emissions have been
evaluated. These are reported in full by Wilton (2004) who adopted 10 study areas for
the Auckland region. Different assumptions have been made for the different areas on
TP292 Auckland Air Emissions Inventory 2004Page 30
the basis of survey and census results. The key assumptions, and the range of values
adopted for the 10 study areas are:
2% - 15% of new dwellings install new burners
5% - 50% decrease in the number of open fires from 2001 to 2021
50% - 90% of households replacing burners will choose new burners, with the
remainder choosing electricity or gas.
This report is based on the same methodology however it is assumed that solid fuel
burners are replaced after an average life of 20 years (as opposed to 15 years in the
original report). The results of projections (percentage reduction compared with 2004
emissions) are summarised in Table 5.1. The projection scenarios are:
1. Baseline scenario from the 1998 and 2004 inventories. This scenario
assumes no improvement in average domestic fire emissions factors (so does not
take account of newer burners having better emissions performance). A gradual
reduction in use of domestic wood and coal burners is assumed.
2. All new burners installed from 2001 meet a 4g/kg emissions limit as specified
in the Proposed Regional Plan: Air Land and Water. This emissions limit applies
under test conditions. “Real world” emissions are generally higher than in
controlled test conditions, so an emissions factor of 6g/kg is assumed for these
burners (reported as baseline scenario in Wilton (2004)).
3. All new burners installed from 2006 meet a 1.5g/kg emissions limit. A “real
world” emissions factor of 3g/kg is assumed for these burners.
4. 80% of new burners installed from 2006 meet a 1.5g/kg emissions limit. The
remaining 20% are unregulated domestic fires. An emissions factor of 10g/kg is
assumed because unregulated domestic fires (e.g. open fires) can have high
emissions. Unregulated burners also tend to have low efficiency, so will burn
more wood to deliver the same amount of heat. A wood consumption rate of
30kg/night is assumed for unregulated domestic fires (compared to an average
fuel consumption rate of 19kg/night for woodburners).
The baseline scenario assumes no improvement in emissions factors over time. This is
unrealistic because new burners are expected to have lower emissions. The baseline
scenario provides an indication of the expected reduction in emissions due to predicted
reduction in the use of wood and coal for domestic heating.
Ministry for the Environment has recently promulgated a National Environmental
Standard for wood burners. The standard requires new wood burners in urban areas to
meet an emissions standard of 1.5g/kg from September 2005. The 1.5g/kg scenario
described above applies to all new burners (including any coal, multifuel and open fires)
in all areas from 2006, so the predicted rate of reduction could be affected if significant
numbers of coal, multifuel or open fires are installed (as suggested by scenario 4).
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